Centering veritally with CSS can be a challenge at times, but not with easy snippet. Make sure the parent class has a relative postion. You can then create the child content to be centered within the parent. This CSS trick centers vertically and horizontally while being 100% responsive.

CSS Centering Snippet

.parent {
  position: relative;
}
.child {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}